This series and parallel sensor circuit was found in Popular Electronics from the 1990s. Any SCR can be used and the supply voltage depends on the load.
This circuit allows you to modify the resolution of a measurement bridge. It was found in the...
In the figure we have a three-phase AC motor control for voltages up to 600 V or 1200 V depending on...
This small experimental transmitter with the CK722 transistors was found in Radio Electronics...